People have noticed that there games that are removed lately for various known or unknown (to us) reasons...
For example:

IGOR Removed Engine Supported Game:
- Igor: Objective Uikokahonia

MADS/M4 Removed Engine was used for these games:
- Orion Burger
- Ripley's Believe It or Not!: The Riddle of Master Lu

Mohawk Engine removed Games:
2018.06: DevTeam Remove detection entries for these games:
- In the 1st Degree
- James Discovers/Explores Math.
- Logical Journey of the Zoombinis
- The Treehouse.
- Where in America is Carmen Sandiego?.
- Where in the USA is Carmen Sandiego?
- Where in the World is Carmen Sandiego?.

Wintermute seems to be way more restrictive with engineid detection. This change is good, but possibly needs a way to be able to add (for testing purposes) unknown games?

Can someone verify on the reasons they got removed and if there are plans for those to come back sooner or later?
Thanks.

Can someone verify on the reasons they got removed and if there are plans for those to come back sooner or later?
Thanks.

The ScummVM wiki for the Igor engine calls it "Incomplete, development stalled. The existing code just allows to play the game demo." The page for the M4 engine is less clear, but from what I remember (someone correct me if I'm wrong) neither Orion Burger nor The Riddle of Master Lu were even remotely playable with it.

I think none of these games are officially supported. To me it seems that what you are seeing is the difference between a release build (that includes only the supported games) and a development version (such as the daily builds, that also include games that are in development or whose development was started but as stalled).

And I forgot, but yes indeed some engines have been removed in the past, including Igor and M4, due to the engines being incomplete and games unplayable, and no developer working on those. Those coming back would depend on whether a developer who wants to work on them shows up.

Regarding the Mohawk engine, the detection entries for the unsupported games where indeed removed in May 2018 (and not June) and this appears to have been a deliberate action. I don't know the reason by I assume this is again because no developer was working on those and thus they would not have become playable anytime soon.

And sorry, my earlier message was completely off the mark and I don't think the release vs. development build had anything to do with any of the engines and games you listed. I read your message too quickly...

As I was lurking the M4 Engine process since several years, I can definitely say that it was never in a playable state and also since several years absolutely no development. Its sad, as I was hoping for progress, but for the ScummVM project its better to remove it until someone with experience and patience is make them playable. Blade Runner for example is a good example for a development started outside the official ScummVM branch and just got added after it was clearly making progress.